Blacklisted
by GaleSynch
Summary: In which being conceived under a potion meant for deception is another similarity Tom Riddle and Harry Potter happen to share. And to think Regulus Black only wanted to pass on information about Horcruxes to the Order; he hadn't meant to pass on the Black family name post-mortem, however accidental. Harry-is-RAB's-son AU.


**Harry Potter © J.K. Rowling**

 **Title:** Blacklisted  
by GaleSynch

 **Warnings:** Minor character death, but major to me 'coz RAB's my favorite character. No Overpowered Harry, just no. He'll grow at a human rate.

 **Genre(s):** Friendship, Fantasy, and add-ons of humor.

 **Note:** This was inspired by an abandoned one-chapter fic of **Harry being RAB's son**. I like the idea but was disappointed when I noticed it's been years it was last updated. So, I decided to start one. This story won't be overly long; I can guarantee it won't be over the 50-chapter mark. Maybe it'll be told through drabble style, perhaps 2k+ a chapter.

Enjoy:

* * *

Chapter I: Great, Just Great

* * *

Braving a Muggle pub was the last thing Regulus Arcturus Black wanted to be doing.

Yet, braving it he was doing. The foreign devices, odd attires that showed too much skin and the violent flashing lights made him jittery. All that dancing—if they weren't rubbing bodies to keep warm for some reason—pressed the crowd onto his person and he wove his way through the throng of disgustingly sweaty Muggles to reach his target.

There, sitting in a loose ring on a small corner, laughing and chatting, unknowing.

He kept one palm on the Dark Mark. Even though he knew in this form, no one could see it.

Sirius looked up first. His grey eyes were striking even in the unnatural lighting. His handsome brother's mouth curved into a brilliant, fond grin at the sight of him: it nearly stunned Regulus because he hadn't seen that smile in years.

"Prongs, c'mon man—what're you doing standing there?"

Ah. Yes. Regulus was reminded why Sirius was even smiling at him; he thought he was James, which, obviously he wasn't. But Sirius wasn't looking at James Potter at all: it was a Death Eater in disguise, and he didn't know it.

Regulus hesitantly picked the seat next to Sirius, as his brother was the person he felt could be trusted—even though his dear big brother wouldn't share the same sentiment. He glanced at the faces surrounding Sirius, recognizing Pettigrew and Lupin—the old gang.

Lupin slanted him a curious glance when his stare was lasting too long.

Regulus wiped sweaty palms on his knees, trying to find his voice. He noticed something completely unnecessary in his desperation to keep his cool: Potter's trousers were made of fabric as rich as what Regulus was used to. A reminder that no matter how much of a Muggle-loving fool Potter was—to the point of marrying a filthy Mudblood would sully the Potter line with half-bloods—he was still a rich man.

The sudden weight on his shoulder, Sirius' arm slung around him, startled him.

"Loosen up, Prongs," said Sirius, laughing at his expression, "It's not like we've drugged your drink. Evans—oh, sorry, Mrs. Potter—is on her way, coming from her parents, she rang. Things will go as plan, no worries."

What plan?

Potter's plans had nothing to do with Regulus. He was here for one thing, and only that thing: to pass on information, to defy the Dark Lord.

Regulus wondered if he was pushing it. This would be the third time he defied the Dark Lord—even though the man never knew it. Never suspected of weak, quiet, unnoticed Regulus who couldn't do anything without Bellatrix guiding his hand. Never really saw how Regulus hid a Mudblood's infant that had never done anything wrong, that hadn't even begun _living_ for Merlin's sake. Never paid enough attention to notice Regulus had let one Order member flee a massacre.

Regulus was never angered by the taunts the senior Death Eaters tossed his way. He would rather be underestimated; no one would know what was coming if he snapped. Not that he would.

"Listen, Sirius, I need to tell you some—" Regulus was relieved the Polyjuice Potion masked his voice: James Potter's unfamiliar husk rasped through his mouth.

"Have a drink," Sirius interrupted, not seeming to have heard, and maybe he hadn't; Regulus could barely hear himself. He forcefully pressed a glass of chardonnay-colored—or some shade ranging from yellow to brown, he could hardly tell with the ever-changing neon colors in here—into Regulus' palms. James' callused hands fumbled with it.

Regulus had never drunk anything Muggle-made before. But his nervousness had dried his throat. He gulped the whole glass down.

Pettigrew laughed nervously, watery eyes bright with adoration and guilt. Lupin shook his head, saying something lost to the increasingly loud music.

And gods, was it even music? It was a continuous assault to Regulus' eardrums: like Blasting Curses being flung each second, to a certain tempo, and the words were lost in the roaring.

"Sirius!" Regulus raised his voice. Sirius didn't look at him, busy as he was ogling a Muggle woman's arse. _Disgusting, sleazy git—_ Regulus broke off. He had only one and a half hour: the Polyjuice potion Severus had brewed with careful care wouldn't last any longer, in spite of Severus' expertise. The younger Black figured now wasn't the time—or place—to chide Sirius harshly for his indecent behavior.

Regulus gripped his brother's elbow and wrenched.

"What? Lily said she's coming in five—oh, there she is!" Sirius' attention was quick to jump around. He poured Regulus another glass of alcoholic drink and urged him to drink up. "If you're nervous, just drink; it's guaranteed to loosen you up."

Really? Loosen up … a Muggle version of a truth serum? Great. Sirius could call "James!" and he'd say, "Regulus," and give himself away.

It was going to incense Sirius—and the other Order members—into possible violent behavior.

Risky? Yes, but it was his best bet. Regulus was banking on the fact that they'd thought he'd kidnapped Potter and would keep him alive long enough to demand questions. A span of time that he would seize to explain about Horcruxes.

Regulus feared there were more. And he only knew where one was. Dumbledore could take over the rest, it was Regulus' best hope to get rid of Voldemort.

Regulus gulped down his drink.

"James!" Before Regulus could say anything, a mouth covered his own. Red hair tickled his cheek. His eyes bulged. He wrenched away, slammed into Sirius, eliciting a shout of protest from his brother, and gaped in horror at Lily Evans.

She'd kissed him! A Mudblood sullying his lips!

Regulus was visited by the sudden urge to Scourgify his mouth. However, the reminder of his personal mission kept him frozen stiff. _Do not overreact, this is your chance to speak_ , he commanded himself. And he looked up once more.

Evans blinked in honest surprise. At first, Regulus thought the Polyjuice Potion had worn off but then her expression turned into one of concern, then wry amusement.

"Have you been drinking much, James?" she asked.

Eloquently, Regulus said, "Er…" He noticed Evans was showing too much skin even though the black dress did much justice to her red hair and brilliant green eyes. Noticed that his head was pounding, his vision blurring. Was he drunk? He hoped not, he wouldn't know. He'd never drunk anything stronger than a Butterbeer before.

"Meh, it's just been two glasses. I'll pour you a drink." Sirius offered Regulus a third glass.

"Sirius, it's urgent, I need to tell you about the Dark Lord's Hor—"

However, his brother only seemed to have caught 'urgent' and 'hor-' because his expression changed into something awfully lewd.

 _What did I say?_

"Urgently horny, you say?" Only years of being taught to control his facial expression stopped his jaw from dropping. "Lily can care of that for ya, you lucky man!"

If only he knew Regulus' real fate— Sirius shoved his unwitting, disguised younger brother off the couch. Regulus struggled to his feet.

Something was wrong—the lights were blurring, the world smearing into dark colors, and his head spun like he was pirouetting—maybe it was a side-effect of the Polyjuice? It was unlikely Severus screwed up but … ugh …

"James?" Evans' voice sounded faraway. "Yep, definitely drunk. I'll bring him up to our hotel room. See you guys later…"

"Wait," he slurred, "Siri—us…"

Evans dragged him away.

* * *

 **Blacklisted**

* * *

The ache of returning to his own skin snared Regulus out of his slumber.

His head was killing him. The naked skin of his shoulder blades was begging to be shielded from the cold.

… Naked?

Groggily, Regulus raised his head, simultaneously forcing his eyes open to see what on earth was going on. He saw a splay of red hair. His pale fingers—not Potter's slightly tanned ones—were threaded in the hair.

Hell.

Regulus tore his hand away, wrenched his whole body away, and fell off the bed, naked as the day he was born. Horror didn't waste time settling in. He located Potter's trousers and wrestled it on, uncaring of how it wouldn't fit him: Potter was taller than him by a foot.

He spun around, though his head complained, and searched frantically for his wand. If the Polyjuice was only wearing off now, it had been an hour since he'd been knocked unconscious by the drink Sirius had handed him. Did Sirius know then? Why hadn't he been arrested if they knew the Death Eater was there?

What business did he have waking up naked in bed with—with … _Evans?_

Regulus nearly screamed when he realized Lily Potter née Evans had been sharing his bed. No, not his bed. Where _was_ he?

Regulus seized the edge of the night table to steady himself, knuckles whiter than his paling face as he searched his most recent memories thoroughly. He remembered entering a Muggle establishment—a five-star hotel, or so they call it—and it would've been a classier place had there not been a pub permitting sleazy association to be carried out in the basement of the building.

He'd been searching for Sirius. To warn him of the Dark Lord's immortality.

As far as his memory stretched, he hadn't even gotten the chance to finish his introduction sentence.

Regulus ran a hand through his black hair, staring unseeingly at Evans bare back, and the pool of red hair on the pillow. He had no recollection of what happened after Evans had volunteered to escort him out, to … to her hotel room … and by Salazar, he hoped their state of undress had not meant what he thought it meant.

The Mudblood stirred. Shifting in her sleep, reaching out for a source of warmth—the source which was Regulus until two minutes prior—that was not there, her hand searching.

Regulus did the only thing he could think of.

Gripping his wand tight, he pivoted on his heels and Disapparated with a crack that woke Lily.

* * *

 **Blacklisted**

* * *

Regulus told no one of that unwitting tryst.

He couldn't bear the shame of it—what would his parents say?

 _Great hero you're being, Reggie, sleeping with a Mudblood and worse, someone else's wife,_ he told himself bitterly as he clambered onto the boat that would sail him to his possible death. He had no clear idea what awaited him on the little island that, according to Kreacher, had a basin and a Horcrux, aside from excruciating pain and hallucinations.

If he was lucky, he'd only hallucinate about copulating with a Mudblood.

If not, well, he was going to die either way.

Guilt gnawed at Regulus. It bit harder with each meter closer to the island. Regulus had did his utmost best to avoid the Potters—and the Marauder gang—ever since that night, nearly two months ago now. Had he ruined the Potters' marriage in his misguided attempt to be a hero? He'd tried to warn them but had ended up sleeping with Potter's wife and the shame had kept him away in the end.

A part of Regulus wanted to lay all the blame on Lily. How the hell had she _not_ noticed he wasn't her husband?

Was it really that tiring for a sober person after sex?

Or was it so lame she was asleep before it was even over?

That did little for Regulus' self-esteem.

Regulus reached his limit the moment he'd set foot on ground again. "Kreacher," he sobbed the name of his only friend, sinking to his knees, and confessed to the house-elf his most humiliating night.

Regulus already knew he was going to die months ago, when he realized he could no longer accept the Dark Lord as his Master. No one defied the Dark Lord and lived to tell the tale, not for long anyway. He'd been semi-prepared for death. He knew he'd done unsavory things as a Death Eater and he'd face his punishment sooner or later.

Yet, when he tried to do some good in this world to atone, he'd somehow warranted utter humiliation from the universe?

Regulus had his own morals, and sleeping with someone's wife was stamping on those morals.

Why could he never seem to do any right?

"Oh, Master," whimpered Kreacher. Instead of cringing in disgust, the house-elf had come over, flinging his arms around Regulus' bicep. "Kreacher will see to it at once! Kreacher will—!"

"Say nothing," Regulus finished miserably. It felt slightly freeing to finally tell his tale of woe. Short, but miserable: a few simple words to describe his short life.

(Short could define him actually: short stature, short life, short achievements, etc. but generally, Regulus tried not to dwell on it.)

"I only needed someone to … to listen, to care—I didn't mean any of it. If … if the opportunity comes, tell them I'm sorry—will you?" He turned imploringly to the house-elf.

Kreacher's wide eyes were glassy with tears as the house-elf nodded vigorously.

"Great, great … then let's do this." Then Regulus stood to face his ultimate enemy and downfall: a basin.

 _Great, just great._ Regulus always said that in bitter sarcasm when situation went from bad to worse.

(Great was his favorite word, whether it was used in sarcasm or as a genuine compliment. Yet, he was never great. Nothing was ever great to, and about, him.)

 _A lame life, a lame death; it should be on my epitaph._

But that didn't stop Regulus from draining the basin's contents.

("Go, Kreacher … hurry!")

Sinking into the depths of watery grave, body locked in the tight, unrelenting grip of the dead Inferi, Regulus expected his life to flash behind closed eyes. Like how the cheesy old folklore went.

But, no—

For an inexplicable reason, Regulus saw a boy who looked just like him in his mind's eye.

And his eyes—his eyes were green and grey. Different colors in each eye. Regulus tried to speak, tried to reach him.

But there was nothing to be reached. No hand offered salvation to be grasped.

The illusion faded with the consuming burn in his lungs and Regulus sank into the depths of the lake, eyes closed.

* * *

 **Blacklisted**

* * *

Seven months after Regulus Arcturus Black was declared dead, a boy with eye colors that would one day evolve respectively into different shades of grey and green, was born.

Lily named him Harry.

* * *

 **Blacklisted**

* * *

 **Afterthought:** Regulus' personality was never really elaborated on. I portrayed him as such based on how Sirius spoke of him: regretful and contemptuous and belittling. I've always wondered if Sirius' treatment of Regulus had given the younger brother lower self-esteem. Not as bad as Wormtail's or Hyuga Hinata's level of bad, just - Regulus doesn't strike me as the type to swagger like Draco Malfoy with an alarming amount of self-confidence. Maybe a whole lot more pessimistic.

 **Question:** Who do you imagine as RAB? I didn't agree with Tom Moorcroft's portrayal of Regulus. Just ... no.

 **R &R**


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